We can give them people instead of mechanism. Let the mentors ban chat - retainers - crafting / gathering - combat specifically. The duration of said ban based on the number of mentors who "reported" the bot.

For example:
A player is gathering using a bot. A mentor can then ban their gathering for 3 hour once a day. If two mentors report them during a month they get ban for 24 hours instead. If 3 mentors do it, they get gathering ban for a week etc. Then we just need a GM to collect the heavily reported players for a permanent solution and maybe another GM to remove the mentor status from players who abuse the system.